The present invention relates to a new exercise bike with two footboards. It is foot-pedalled and moves forward in a fluctuating manner.
Exercise bikes that appeared in recent years are mainly meant for sport and competition, both for entertainment and body building. The construction of an exercise bike can apply the principle of loose-fitting between a crank shaft and its base. This, however, requires a high material hardness and a high manufacture precision of the shaft and its base; and the bike is, therefore, difficult to produce. The bike will not operate properly even if there is very slight transformation. Besides, the so-called "massage function" is actually done in a "finger-pressing" manner, which cannot produce the desired effects on acupuncture points. According to the Theory of Jing and Lo (channels and collaterals), finger-pressing is far less effective than "rotating massage". Another exercise bike, disclosed in another utility model CN 90 2 1506.0, announced on Oct. 10, 1990, avoided the defect of using a crank shaft, and can be made entirely of plastics. In the construction of that exercise bike, a straight square-headed shaft instead of a crank shaft is used. The square end of the shaft is fitted tightly into a corresponding eccentric square aperture made in the disk of a wheel. Compared with the aforementioned bike having a crankshaft, it has the advantages of being easy to produce, stronger in structure and handy in use. Nevertheless, both bikes have the same safety problem, that is, a beginner not used to riding such bikes may fall down because of sudden pedalling. There are several types of bikes utilizing a straight square-headed shaft, comprising three wheels, four wheels, or six wheels. The six-wheeled bike consists of six wheels, two footboards, four square-headed shafts and eight half bushes. The square heads of the shafts are inserted orthogonally into the corresponding eccentric apertures in the wheels. Two wheels are provided on each of both the right side and left side of the bike, and each wheel has two apertures provided therein. One end of a shaft is inserted into one of the two apertures of each wheel. Two wheels are provided in the middle, each of which has two apertures. Likewise, one end of a shaft is inserted into one of said two apertures of each of the middle wheels. During assembly, both ends of a shaft must be properly inserted into the corresponding apertures of the corresponding wheels. If they are inserted improperly, for example, as in FIG. 3(i a) the bike cannot be properly assembled. The correct assembling is shown in FIG. 3(b). Since a joint between a shaft and a wheel is fitted tightly, it would be difficult to pull out an improperly inserted shaft without causing damage thereto. So, if all the parts of the bike are packed and transported in separate packages to be assembled by a user (i.e., customer), the customer may render a bike useless by making a mistake in assembling, since most customers are not experienced in assembling such bikes. To obviate such problems, a solution would be to sell assembled bikes as the final product. However, such assembled bikes would take up to much space in transportation and are inconvenient to carry. The high cost in packaging and transportation limits sending large quantities of goods (i.e., bikes) over long distances and, therefore, prevents popularizing the products of the greatest invention.